The term fortress world gained prominence during the Clone Wars, when the Confederacy of Independent Systems concentrated self-replicating Techno Union factories, refineries, and assembly lines around planets in the Outer Rim Territories. The Galactic Republic also had fortress worlds, protection of which was among the duties of the Alpha-3 Nimbus-class V-wing starfighters during the war.
If they were left undisturbed, General Grievous's facilities built during the Separatist invasion of Utapau could have turned Utapau into another Outer Rim fortress world.
- Star Wars: Complete Vehicles
- Star Wars Complete Vehicles, New Edition